The present invention relates to an ultrasonic oscillator, in particular for megahertz operation, and in particular further for liquid atomization.
From U.S. Pat. No. 3,904,896 and U.S. Pat. No. 3,738,574 a piezeoelectric oscillatory system, in particular for liquid atomization, is known, with a stimulating oscillator consisting of a bending oscillator plate with transducer plate, the bending oscillator plate being coupled with a thinner working plate by means of a web. Alternatively, the bending oscillator plate and the web may be formed as a truncated cone, merging one into the other, and being in one piece with the working plate. Such oscillatory systems can be used for the atomization of liquids in kHz ultrasonic atomizers. A disadvantage of the known MHz atomizers is that the diameters of the droplets produced are substantially larger. Thus, usually less than 50% of the produced aerosol matter is inhalable. Inhalable aerosol is obtained here only with mechanical separation systems.
Known also is atomization by means of a hemispherical oscillator oscillating in the MHz range. Thereby an aerosol of different diameter, namely of about 0.1 micron to several millimeters, is obtained. The particles of larger diameter must be retained by means of a mechanical droplet separator.